Final answer:
In eukaryotic cells, there are three types of RNA polymerases: RNA polymerase I transcribes rRNA, RNA polymerase II transcribes mRNA, and RNA polymerase III is responsible for tRNA, 5S rRNA, and snRNA. Each has distinct mechanisms and transcription factors for DNA template engagement and termination of transcription.
Step-by-step explanation:
In eukaryotic cells, there are three different types of RNA polymerases that are responsible for transcribing different classes of genes. RNA polymerase I is primarily involved in the transcription of ribosomal RNA (rRNA) genes. RNA polymerase II transcribes all of the protein-coding genes, producing messenger RNA (mRNA). Lastly, RNA polymerase III is responsible for transcribing RNA genes that include transfer RNA (tRNA), small nuclear RNA (snRNA), and 5S rRNA.The initiation of transcription in eukaryotes is a complex process that involves the binding of several transcription factors to promoter sequences, which are typically found upstream of the gene in question. Each RNA polymerase operates within a distinct mechanistic framework, relying on specific transcription factors to engage DNA templates. Furthermore, the termination of transcription differs among the RNA polymerases; for instance, RNA polymerase II transcribes well beyond the coding region and involves subsequent cleavage during mRNA processing.